One of the therapeutic procedures applicable to the present invention is known as percutaneous transluminal coronary angioplasty (PTCA). This procedure can be used, for example, to reduce arterial build-up of cholesterol fats or atherosclerotic plaque. Typically, a guidewire is steered through the vascular system to the lesion site of therapeutic interest. A dilatation catheter is inserted over the guidewire and is tracked along the guidewire to the lesion where the catheter is inflated to dilate the lesion. A guiding catheter acts as a support conduit for both the guidewire and the dilatation catheter. The shape of the guiding catheter, and particularly the distal shape, strongly influence the ability of the physician to position the tip of the guiding catheter within the target lesion. Further, the distal shape is influential in providing support for the interventional device as the physician attempts to manipulate the device within the vasculature of the patient.
Many catheters use the femoral artery approach in the patient's leg. The disadvantage of the femoral approach is the length of time the patient is required to remain in the hospital. With the femoral approach, the size of the puncture site will range from 5 French (F) in a diagnostic procedure to 10 F in an angioplasty procedure. The majority of femoral procedures world wide are performed with 7 F or 8 F catheters, while approximately 15% of femoral procedures are performed with 9 F or 10 F catheters. Once the catheter or sheath has been removed from the femoral artery after arterial access, the femoral puncture site bleeding must be stopped. This can be done by manual pressure applied from 10 to 40 minutes, or by a compression assist device which may be used for a similar amount of time. Typically compression will be administered in the catheter laboratory following a diagnostic procedure or in the cardiac care unit or holding area following an angioplasty procedure. With either method, the patient must lie supine for a minimum of four hours, and remain in bed for an additional 16 to 20 hours. The patient must be monitored by hospital support staff during this time.
Because the radial artery is smaller than the femoral artery, a typical size of a radial guiding catheter for angiographic or coronary applications is 6 F. The advantage of a radial artery approach in the wrist is that the wrist puncture wound is smaller than the femoral puncture wound and hemostasis is achieved faster thereby eliminating the patient's overnight stay in the hospital. More rapid hemostasis results in reduced incidence of access-site related major complications.
EP 728,494 to Kiemeneij discloses a radial guiding catheter curve having a distal bridge shaped portion which has a distal arch defining a primary curve which has a concavity oriented towards the proximal end of the bridge. It also has a top defining a secondary curve, the secondary curve having a concavity oriented between the first distal straight portion and the proximal end of the bridge. In addition, it has a proximal arch defining a tertiary curve, the tertiary curve having a concavity oriented towards the first distal straight portion. The proximal arch is connected to a straight shaft. The shaft is stiff and the bridge shaped portion has a flexibility extending at least up to and including the primary curve and a stiffness extending at least up to and including the tertiary curve.
The left Amplatz curve is constructed on variations of a basic shape having a first straight shaft portion followed by a first curve in a first direction followed by a second curve in the opposite direction followed by a second straight shaft portion. Examples of these prior art curves can be found in Medtronic marketing literature UC9001552aEN copyright 1991.
A radial approach necessitates the use of the brachial artery. It is difficult to engage the coronary artery from the brachial artery with the prior art radial curves due to insufficient back-up support. What is needed is a guiding catheter shape better tailored to the anatomy so that the guiding catheter will orient coaxially with the coronary ostium for the interventional device as the device is being manipulated through the vasculature to the target lesion. It is an object of the invention to provide improved back-up support in a radial approach guiding catheter.